feat: Catch types in Cargo.toml and warn about them

Cargo.toml

@@ -25,6 +25,7 @@ openssl = { version = '0.10.11', optional = true }
 parking_lot = "0.6"
 serde = "1.0.74"
 serde_derive = "1.0.74"
+serde_ignored = "0.0.4"
 serde_json = "1.0.26"
 siphasher = "0.2.3"
 slog = "2.3"

src/lib.rs

@@ -17,6 +17,7 @@ extern crate parking_lot;
 extern crate serde;
 #[macro_use]
 extern crate serde_derive;
+extern crate serde_ignored;
 extern crate serde_json;
 extern crate siphasher;
 #[macro_use]

src/manifest/mod.rs

@@ -15,6 +15,7 @@ use failure::{Error, ResultExt};
 use progressbar::Step;
 use serde::{self, Deserialize};
 use serde_json;
+use std::collections::BTreeSet;
 use toml;
 use PBAR;
 
@@ -210,8 +211,25 @@ impl CrateData {
         }
         let manifest = fs::read_to_string(&manifest_path)
             .with_context(|_| format!("failed to read: {}", manifest_path.display()))?;
-        let manifest: CargoManifest = toml::from_str(&manifest)
-            .with_context(|_| format!("failed to parse manifest: {}", manifest_path.display()))?;
+        let manifest = &mut toml::Deserializer::new(&manifest);
+
+        let mut unused_keys = BTreeSet::new();
+
+        let manifest: CargoManifest = serde_ignored::deserialize(manifest, |path| {
+            let path_string = path.to_string();
+
+            if path_string.contains("metadata") {
+                unused_keys.insert(path_string);
+            }
+        })
+        .with_context(|_| format!("failed to parse manifest: {}", manifest_path.display()))?;
+
+        unused_keys.iter().for_each(|path| {
+            PBAR.warn(&format!(
+                "\"{}\" is misspelled and will be ignored. Please check your Cargo.toml.",
+                path
+            ));
+        });
 
         let data =
             cargo_metadata::metadata(Some(&manifest_path)).map_err(error_chain_to_failure)?;